The present invention relates to an apparatus and a method of inspecting, after a transparent reagent for reaction with blood is applied on an electrode, an applied condition of the reagent (an amount of displacement of the transparent liquid from a predetermined application position and surface expansion of the transparent liquid), for example in a manufacturing process of a blood glucose value sensor for measuring a blood glucose value of a human.
As shown in FIG. 6, in a process of manufacturing, from one base material 7, a large number of pieces of a multi-piece product 22 each applied with a transparent liquid 50, applied conditions of the transparent liquid have been visually inspected by an inspector.
However, inspection accuracy and inspection efficiency are low in the visual inspection by the inspector, and thus reliable products cannot be produced, and also production speed is low to prevent high volume production. In this view, inspection of an applied condition with high accuracy using an automated instrument is desired for ensuring reliability of a product and increasing production efficiency. Thus, attempts have been made to automate inspection of an applied condition using an image processing technique.
To automatically inspect the applied condition by the image processing technique, a boundary between the base material and the transparent liquid needs to be identified. For this purpose, a method has been considered in which surface tension of the transparent liquid is used and an end of the transparent liquid is illuminated to cause the boundary to emerge for identification.
However, when the surface tension of the transparent liquid is low, the transparent liquid penetrates the base material, and the boundary between the base material and the transparent liquid does not emerge even if the end of the transparent liquid is illuminated, thereby causing difficulty in identifying the boundary between the base material and the transparent liquid. Further, the base material actually has a background (for example, a printed electrode pattern in the blood glucose value sensor), and thus a contrast between the base material and the transparent liquid and also a contrast to the background need to be considered, thereby further causing difficulty in identifying the boundary by the image processing technique. Therefore, a method of automatically inspecting the applied condition of the transparent liquid by the image processing technique has not yet been established.